Control system



:May4,1937;r j HQHGORRIE 2,079,165

CONTROL SYSTEM original Filed `may s, 1931 /00 50 il U 6 v LAL 6a 4 69 3lNvENToR operation of apoweiuproducing or usingappara- `5tus, and inparticularfitisrconoernedlwitnthe control of the feedngfof theelementsof com@` I j p bustion to avaporgeneratirlg 01 heating appara:

`tus, aswellas` with the proportioning andheating offluid'sfin suchanapparatus. r i

` iithavechosen toillustratexand'willlblescribeVapreferredembodiment'ofmy invention,"in connection *with a primary steamgenerating boiler t adapted to utilize ther-Wasteproducts oncombus-` n3i `tionfor heatingtthewsecondary steam exhausted "Vision forsupplementing theheating` of thewsectondary steam `by means ofprimarystearn. r

I Oneof` the objects `oftheinventionisto control the feeding of theelements ofslcombustion to a "vapor generating boiler `inproportiontothe r i in the `vvastegproducts or-combustionfor `reheati r g5 ingthevaporgeneratedbyithe boiler after it has I givenfup someiofu s-fheatcontent in a utilizing apparatusl` r illustrated inthe drawing' which is`a somewhat `x` .diagrammatic representationmof"a"steam `gen-- erating4boiler in sectional elevation; andto `which theinvention hasqbeenapplied.

I have illustrat dY enerallyfat Ila steam"gen-4 erating boiler having a@combustion chamber r2 j supplied with fuebsuoh as oil-or`gas,forexample!l` i Q" througha burnerpS, andwith air for combustionV`50 throughftheyconduitf4. The `rateyol `admission I. `yof lfueltothe.furnace1isqcontrolled,through.the "@positioning :ofa valveti5` byavreveifsible` means illustratedasga reversible electric motor.. The irateof feed off airtogthe furnaceas anqelement l of combustion throughthe conduit'is controlled trom a primarystearn utilizerf and` havingfprovi-fA "heat desiredfto be utilized VfrornftheWaste prody l f Another`object is to utilia'ez thelheat i contained y. I Stillanother objectislto-providemeans for sup` ""pleme'nting, bythe heattof apartof thevapor Wan these fandfutnn tiene iavw, I Awur now`.describetheembodiment" ofjmy invention" r `Between that turbine I5 y I I ao'iawsV"CONTROL SYSTEM# i K 11arvam1f1`I ,zdonn;Clevelandinsights.omoa as- I I.signor toBailey` "Meter Company, afcorporation y original lappiieationl-Mayfa 1931, serial I no. i il :535,999. Divided and`- thisapplication May 20,l pr 5 g p 1 1935, Serial No."22,4`25 i i t I y I oiotolains;Hermanos) r r Myinvention relatesto `controlsystems such `asmay` be employed` for, the automatic control s `of` certain" variablefactorslor conditions in theg` by th DSltOning of; afdarnper 1relatively across-r the Conduit *wbr arversime` meansiuustrated.

as `areversible,electrici-motor 8.` i `Heat liberated through combustionin `,the

chamber 2, generates steam which collects in the 5 ratus illustrated asasteam turbine Y. I5.r` While 10 in thepractice of my invention it isnotneces-` sary that therer be more than a singlevapor "gen-l` erator and asingle vapor utilizer, I have for the vsake of clearness ofunderstanding, shown a secf` `ond branch |00 leadingfrom the header I3to a i 15 steamntilizer and` a branch" IDI joining .the` header I3 froma` steam generator. l

Thesteamexhausted from theturbine I5 isf desirably i reheatedor suppliedwith additional r heat; after havingpasse'd` through `the turbinetsoV 20`that it maybe used in a `second utilizing appa.-

ratus such V.asgwajlovver `pressure turbine, (not g shown), and passestojthesecond utilizingappa-` ratus` through a pipe I6, joiningtheturbinefIS` at its exhaust end., In the pipe I6 is `desirably 25placedla. heater comprising a number of relat tively smaller heatingtubes I1', `positioned at `the f outletofgthe `gastpassage through theVboiler `I I and subjected, in heat conducting relation, to

the eiect: of` the heat Acontained in the waste 30 products ofcombustion leaving theA boiler; the

` flow of` the products of combustion being con--` trolled bythepositioning of va damper, Ill` bye. reversible" means illustratedas` avreversible elec'-` tricmotorI9.V r I i I .I

r At theoutlet of the heating tubes I1 and in the/pipe, I6,` Ipreferably install 'a thermostatic bulb `2l), forming a part; of agas-filled thermomf` eter systemof Whichl2I isya Bourdon tube, con#leaving .the heater I1.

`have shown a bypass connection 23 to the pipe` and the heater |1`ILnected to the bulb ZUbyapipe 2 2;the bulb 2l!A 40 sensitive totemperature of the reheated steam `|65 the owof. steam throughthebypassf23 be, 45

ing controlled by a valve means 4'424, positioned by a reversible'meansillustrated as a reversible lectric motor25. The motor` 25 is under thecon- `trol of-fulcrumed contactor 26, positioned relative .towcontactpoints 28 and 29 through the 50H departure r from a predeterminedtemperature, ofthe` indicator arm 21 attached to the Bourdon`,Inserted-in "the bypass line 23 is a `heat en# changerthroulhWhichsteam passes fronithe 55 y pipe |6 andaround the heating coils 3|'I'he coils 3| are supplied with relatively higher temperature orprimary steam from the boiler drum 9 through a pipe 32 and condensatefrom the heating coils 3| returns to the drum 9 through the pipe 33.There are no valves shown in the heating system comprising the' pipe 32,the coils 3| and the pipe 33, so that flow therethrough is controlledentirely by the condensation of steam through heat transfer within theheater 3|, the condensate returning through the pipe 33 to the boilerdrum 3 through the gravity head of the difference in elevation betweenthe heater 3| and the drum 3, the steam pressure being balanced betweenthe two. It will be seen that primary steam for heating, is alwaysavailable through the pipe 32 to the heating coils 3|, and the amount ofheat exchanged will depend upon the 4amount of lower heat content orsecondary steam passed through the pipe 23 to the pipe |6, around theheating coils 3|, which in its passage tends to cool the coils 3| andcondense the steam within them.

Thus the heat which isv added to the steam flowing through the pipe |6,prior to its reaching the heater I1, will depend upon the amount of saidsteam bypassed `through the pipe 23 and thus upon the positioning of thevalve 24. The positioning of the valve -24 has been shown to depend uponthe temperature effective upon the bulb 23 of the thermostaticallyoperated contacter 26, and the bulb 26 is sensitive toa temperature ofthe steam after it has passed the heater |1. Thus the steam passingthrough the heater l1 absorbs heat from the waste gaseous products ofcombustion passing fromthe boiler and if the heat so transferred fromthe products of combustion is not suiiicicnt to raise the temperature atthe bulb 20 to a predetermined desirable point, then the variation ofsaid temperature from a predetermined value will effect a positioning ofthe contactor arm 26 and correspondingly of the valve 24, to bypass apart of the steam a conductor 34 to the power line 35, and by aconductor 36 to the contact 28, and by a conductor 31 to the contact 29.vT'he contact bar 26 is connected through a conductor 38 to'the otherpower line 33. From the contact arm 26 I lead the conductor 38 throughan interrupting finger 40, through whose agency the conductor 38 isperiodically disconnected `from the contact arm 26 by means of a cam 4|driven at desirab'ie speed of rotation by a continuously operating motor42 connected directly across the power lines 35 and 36 through theconductors 34, 38. Thus I have provided that the movement of the valve24 will occur by intermittent operation of the motor 25 rather than acontinuous operation of the same, to prevent overtravel and hunting.` f

In the embodiment here illustrated, all of the steam exhausted from theturbine I passes through the waste gas heater` I1, and I desirablycontrol the rate of combustion in the furnace 2, such that the heatavailable in the waste products of combustion will be in proportion tothe rate of flow of the steam through the heater |1. With a constantrate of steam passing through the heater |1, if I allowed the combustionrate within the furnace 2 to decrease, then the steam passing throughthe heater would not be heated to the desired temperature; or if I allowthe combustion rate within the furnace 2 to increase relative to thequantity of steam passing through the heater, then the steam will beheated to a higher temperature than desired.

The steam passing through the heater |1 from the pipe I6 is directlyrelated to the load on the turbine |5, and is the same steam admitted tothe turbine through the pipe 4, so that I may take as an indication ofthe steam passing through the heater |1, either an indication of theload on the turbine I5 or a measure of the steam flowing through theturbine, and have in the present illustration shown the invention asutilizing a measure of the steam passing to the turbine through the pipeI4. Inserted in the pipe 4 is shown a'flownozzle 43 as a means ofcausing a temporary increase in velocity ofthe steam, for producing apressure differential bearing a known relation to the rate of ow of thesteam .through lthe pipe, and said pressure differential is madeeffective upon a steam flow measuring meter 44 to position a pointer45.relative to an index 46. I lead to the flow meter 44 a pressure fromthe inlet side of the flow nozzle 43 through a pipe 41, and from theoutlet side of the ow nozzle 43 through a pipe 48. The flow meter 44 isof a type Well known in the art, having a liquid sealed bell adapted tobe positioned vertically responsive to variations in a pressuretransmitted through the pipe 41 .and a pressure through the pipe 48effective within and without the bell re spectively, suchverticalpositioning producing angular movement of an indicating arm 45relative to an index 46 in a clockwise direction of rotation for anincrease in the'rate of flow, the wall of the bell being so shaped as totranslate the non-linear relation between rate of flow and differentialpressure to a linear relation.

As an indication of the rate of operation or output of the boiler I takea measure of the steam generated by the boiler and passed through thepipe |2 to the header |3. Inserted in the pipe |2 is shown a flow nozzle49 for creating a pressure dierential bearing a known relation to therate of flowy ofr steam therethrough, and said pressure differential'iseffective upon a flow meter 50 through the pressure pipes 5| and 52 forpositioning an indicator 53 relative to an index 54. 'I'he flow meter 50is similar to the flow meter 44 and is arranged in a manner such that anincrease in rate of flow of steam through the pipe |2 causes the pointer53 to move in a clockwise direction over the index 54. Y

By comparing the rate of flow of the steam from the boiler with the rateof flow of steam to the turbine l5, I have a comparison of the operationof the boiler with the demand for such operation or demand for heat atthe heater |1. I therefore desirably compare the position of the flowmeter arm 45 with the flow meter arm 53 and upon a departure fromdesired relationship between the two, I cause to be effected a change inthe rate of operation of the boiler. This is accomplished through thepositioning of a contacter effective in varying the rate of supply offuel and air to the combustion chamber 2, andthe rate of discharge ofthe products of combustion from'the boiler. From the pointer 45 is.suspended a freely hanging link 55, and from the ,pointer 53 issuspended a freely hanging link 56. The links 55 and 56 at their lowerends are joined by a freely floating bar 51 from which is suspended,intermediate its ends, a rod 58 in a manner such thatl when the flowmeters 44 and' 50 indicate the same or desired proportional rate offlow, regardless of quantity, within the limits of their capacity, therod 58 will not bex moved from` its,vfrzrticalI "positionQIf,V howf`ever; `the indications of thevlow` metersl 44 andi s l, 50 varyfromthedesired proportionality, then the` `rod E58 will bepositioned`vertically `eithenqup-z` "ward or downwardand. `int-amount depending if58fserves to movein a clockwise `or counter-clock-` wise rotation an arm59 forming; a Ypart of a contactordevice. L

and when the arm.59\,is moved from a `prede`` terminedjposition, theextension 6l ,may close p82or of the conductor 63.- I.

i proportional to the rate of operation ofthe turbine I5,2[` find itdesirable that i theupressure `of the steam going to the turbine be .ofa prede-, termined value. To'insure this, Lhave provided `a"fi`1rth ercontrol olfl theelements of-,cornbustion to the boiler, sensitive `tovariations in pressure jot the steam. M b

""Connected to theheader`I3is-shown a presw sure pipe 64 fortransmitting pressure from within thepipe i3fto` ardBourdon tubel65which tends Meo Y, s s s f ``c;'ninterclocktvise rotation .for adecrease `in pressure. `f'lhe arm rpositions" vertically a` freelysuspende'dflinle'l, resulting. in an angular posi-` the lowerend `ofthe1inkj 61;" and et its piyoted endeffetive to position an extension 'I8of a` oon- @what illustrated `at so. tofqiose `circula with either thecontact` terminal of the `conductor `1| orl of'thecoridctr 1,2,depending `upon the" direction of departure of `steam,iiressure withinthe pipe I3 from` apredeterrri'ined`vaine;` f f Closnreofcircuitateither ofthe contactors 60, i 68 tendswto" cause a rotation of` thernotors 6, 8

and uneven neutral wireisljeineditt the power iine`35. The switch13`'may `be energized `swltcli14fma`y be""energized nponfclosing ofcircuit by thecontact` arm with the conductor 12,

I interlpckedtnrough the switch 13 at thejswitchf "65 points 11, thecontact` armfflbeingbconnected byconductors 18 and 38 to the other`powerline `39.`

The conductor L18 joinsthe conductor "38 l throughthejinterruptingifinger previously def` scribed "as periodically fopencireuited'fthrough I upon the deviation `between thertwodiowmeter`readings, Such" verticalpositioninglof,thearod` i 3 i In thejcontactor`device`6`l`l,thetarmf 59` has `anl `extension `6I `at the," opposite,side.,of a fulcrum;

circuit with a contact terminal fof the` cenductor velprovided acontroljsystem tending, r f to maintain the ratev ofoperation oitheboiler l l xto" unwindfandinove an `"168 `in a` clockwise rotation`foran increase` in pressure,or in La tioning of an arm 68 connectedatitsireeend to `tactor"indiented generallyatf of similar, type s' s and`fair to the furnace,2fo`r' of althrottlingof `bastion at the boiler.

i The solenoid coils of thefmagneticswitches ,13

"I upon aclosing Aof circuit between the contact arm 18 and theconductor 1I, interiock'ed through 1` switchboints 16 of the switch 14.zSimlarly, the

rotation "oLthe jfcntinuouslydriven cam 4l,

y.: `any energizationof the magnetic Vswitches s131erf`|41throughaclosingof` circuitby thecongftactorarni 10 with the,`conductor 1I"or`wlth the conductor"12 would be intermittent, dependingyupon the interrupting finger. e 1

,-.Uponenergizationof the switch 13A, circuit is closed betweentheconductor 38 and al conductor. `1ajoining the three motors. A returnconductor `8l) leads from the three motors to the power line 35..` Uponthe energization of the switch14, the conductor 38 isjoined toaconductorBI, joining theythreemotors Vfor `an energization of` same inthelopposite rotation. Y l s j VContact of thevarm 6I with the lcontactterminal offtheconductor 62 `closes `circuit between the conductor 19andra conductor82` to vthe `con- "ductors 18,38, and the power line39.,` Contact of `the arm 8| `with the contactterminal fof, theconductor 63 lcloses circuit for the motorsby the Vconductors81,83,contact arm l`IV conductors 82, 18, 38 ,and the poWer line 39, thereturn rfrom the` motors being the conductor. *f y points 83 of theswitch13 and the-switchxpoints 84 of the switchJl, in a manner such thatener.- gization` of `either of the switches 13.: or 14 will breakthecircuit of thewire 82and1prevent the` l energization or actuation of themotors through a positioning of the contactor arm 6I.

,Thus it will` beivseen that whenever the"conA Positioned in theconductor s2 areth switch tact -ann 10 of the contacter` B9 contactswith the `conductors 1I or 12 for an` energizing of the switches 131er14, the circuit is. broken tothe contacter 6 making it ineffective `andgiving precedenceto the contactor.

4lnioperation, assume aconstant load on the steam` turbine, andconsequentlya constantrate of. flow of steam `through the pipe`-l4 asindicated by lthe iiow meter 44, andthat the `rate of iiow `of steamthrough the pipe, I2 to the header"l3 is lessthan the amount taken bytheturbine, so

thata part of the steam passing to the turbine, is suppliedfrom theheader I3.

ucts ofv combustion leaving the boiler AI and availableat the heater`I1-wll have aheating ability l in, proportion to the4 output `oftheboiler, and I will be lower inproportion to the steam from` the turbineflowing` through the heater lthan necessary to raise the temperature ofthelsteam to the predetermined value. Therefore it` is desired that thevrate of combustion at thelboilerI be increased, and that thetemperature` of the steam leaving `the heater I1 be broughtY upV to`the'predetermined value. .Two regulations'are eiectedynamely, abypassing of some of the 4steam owing through the pipe I6, through theheater 30, and an increasing of the rate of com- Divertinga part of theexhaust steam through the heater 30 condenses someof the steam generatedby the .boiler I, andthe output through` thepipe I2 is `furtherrcaduced.The flow meter SII `indicates by a counterclockwise movement of the arm53 a decrease inrateof ,flowthrough fthe flownozzle 48, while the arm`4.'iof theiiow meter remains steady. 'I'he result is a .down` wardpositioning of therod 581and aclosing ofy 'Ihe waste prodcircuit'by thecontactarm 6I with the vcontact l terminal ofthe conductor 82, to theend`that upon the periodic rotation of thecam 4I an intermittent movement`will be effected lof the vfuel supply valve 5, theair supply damperl andthe `exit damper A I 8 through intermittent energi` zation of ,thelcorresponding motors 6, 8 and .I 9.

. The `lack of `heating ability inthe 4waste prod-,-

ucts of` combustion at thefheater I1 resulting in a` temperature of thesteam leaving the heater below the predetermined value, is eiective uponythebulb 20 to produce a positioning `of the contactor 281er anoperation of the motor 35 and a. positioning of the valve 24 in adirection to open for flow through the bypass 23 from the pipe i6 anddivert more of the exhaust steam through the heater 30. l

During the operation above described, whereby more or less of theexhaust steam is'diverted through the heater 30 and whereby entirelyindependently the rate of combustion at the boiler I is increased ordecreased, if at the same time the steam pressure within the header i3increases or decreases relative to a predetermined value, the result isa positioning of the contacter 69 to effect a regulation of the motors6, 8 and I9, taking'precedence over the contactor 60.

Inthe event that all of the primary steam generated by the boiler-I goesto the turbine I5 and no other steam from the header I3 goes totheturbine, the reading of flow byflow meters 44, 50 will be the'same,and the contactor Swill be open-circuited. If now the load on turbine I5increases, calling for more steam, the pressure contactorGS will causean increase in rate' of supply of the elements of combustion, wherebythe steam flow through pipes l2 and I4 will increase and in the sameamount. 1

It will be seenv that I have a control system which, While illustratedand described in connection with a steam generating and heatingapparatus, may be equally as well adapted to other similar apparatus,and I desire it to be'distinctly understood thatl while I haveillustrated and described a preferred embodiment of my invention,

I do not intend to be limited thereby, other than as claimed in view ofprior art.

The present'application is adivision of my copending application SerialNo. 535,999, filed May 8, 193i, entitled Control systems. v

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:-

l. In combination, a vapor generating boiler, means for supplyingelements offcornbustion to the boiler, regulating means for said means,a header connected to the boiler and to which the generated vapor ows, avapor utilizing apparatus connected to the header for utilizing vaportherefrom, a rate of flow meter for the vapor leaving the boiler, asecond meter for the vapor going to the utilizing apparatus, flow ratiodetermining means adapted to be positioned by said meters, and controlmeans for said regulating means responsive to a departure of said flowratio deter-y mining means from a position indicative of predeterminedratio.

2. In combination, a vapor generating boiler, means for supplyingelements of combustion to the boiler, regulating means for said means, a

' header connected to the boiler and to which the generated vapor iiows,a vapor utilizing appatus connected to the header for utilizing vaportherefrom, a rate of flow meter for the vapor leaving the boiler, asecond meter for rthe vapor.

going to the utilizing apparatus, flow ratio determining means adaptedto be positioned by said meters, control means for said regulating meansresponsive to a departure of said flow ratio determining means from aposition indicative of predetermined' ratio, and vapor pressureresponsive means also effective upon said regulating means 3. Incombinatio'n,`a vapor generating'boiler, means for supplying elements ofcombustion to the boiler, regulating means for said means, a

leaving the boiler, a second meter for the vapor going to the utilizingapparatus, flow ratio determining means adapted to be positioned by saidmeters, control means for said regulating means responsive to adeparture of said flow ratio determining means from a positionindicative of predetermined ratio, vapor pressure responsive means alsoeffective upon said regulating means, and means for allowing said lastnamed means to take precedence over said control means.

4. In combination, a vapor generating boiler, fuel and air supply meansconnected to said boiler for maintaining combustion, regulating meansfor said supplying means adapted to vary the rate of supply, a headerconnected to the boiler and to which the generated vapor ows, a vaperutilizing apparatus connected to the header for utllizing vaportherefrom, means positioned responsive to variations in the magnitude ofthe steam demand on the boiler, means positioned responsive tovariations in the magnitude of the steamdemand at the utilizingapparatus, and control means jointly positioned by said last two named.means and adapted upon being positioned away from a predeterminedposition to effect an actuation of said regulating means. Y

5. In combination, a vapor generating boiler, fuel and air supplyingmeans connected to said boiler for maintaining combustion, regulatingmeans for said supplying means adapted to vary the rate of supply, aheader connected to the boiler and to which the generated vapor flows, avapor utilizing apparatus connected to the header for utilizingvaportherefrom, means positioned responsive'to variations in the magnitude ofthe steam demand on the boiler, means positioned responsive tovariations in the magnitude of the steam demand at the utilizingapparatus, control meansjointly positioned by said last two named meansand adapted upon being positioned away from a predetermined position toeffect an actuation of said regulating means, and vapor pressureresponsive means also adapted to effect an actuation of said regulatingmeans.

6. In combination, a vapor generating boiler, fuel and air supplyingmeans connected to said boiler for maintaining combustion, regulatingmeans for said supplying means adapted to vary the rate of supply, aheader connected to the boiler and to which the generated vapor flows, avapor utilizing apparatus connected to the header for utilizing vaportherefrom, means positioned responsive to variations in the magnitudeof'the steam demand on the boiler, means positioned responsive tovariations in the magnitude of the steam demand at the utilizingapparatus, control means jointlypositioned by said last two named meansand adapted upon being positioned away from a predetermined position toeffect an actuation of said regulating means, vapor pressure responsivemeans also adapted to effect an actuation of said regulating means, andmeans for allowing said last named means to take precedence over saidcontrol means.

7. The method lof controlling the supply of elements of combustion to avapor generator supplying vapor toa plurailty of vapor utilizers throughindividual branch conduits connected to a common header comprisingVsupplying elements of combustion to said generator in an amountsuflcient to generate vapor at a rate to meet the full demands of all ofsaid utilizers operating together, and varying the quantity of theelements of combustion supplied to the generator in accordance with thevariationsrin the ratio between lthe generator andthe quantity of4vapornnowing jin one of said branches existinggwhen all utilizersareoperated under normal load.` r

`8. `In a control for a supply ofelements of comlbustion `for a burner,a vapor generating chamber, aheader receiving vapor from the generator,a plurality of"vaporutilizers, branches connecting lthe"he'ade'xywitlzi:the utiiizers` and receiving vapor "header from 'the generator and thevapor `iowing ing the* quantity of 4the? elements of combustion`supplied to the burner in accordance withthevavapor owingto the headerfrom the generator normal vload. l

` `meaxfis for supplying elements otcombustionto the boiler, regulatingmeans `for saidA means. a

l p rp jao'zaieo 1`lthe quantity` yof :vapor owing "to the header from lijtherefrornin 'sucient `qulntity to meet the fullV demands-of allofsaid utilizers, whcerebylsa. ratio `is established between the vaporflowing, to the ,through one of said branches and means for vary-irriati'ons from the ratio'between' the quantity'of andthenquantityof`vapor owinginone of said' branches when' the `utilizers are operating.under l 9. In combination, va vapor generating `boiler,`

`regulating means.

"header connected to the boiler into` whichV the generated vapor flows,a vapor utilizing apparatus y connected to the header for utilizingvapor therel fromya rate of ow meter forthe vaporleaving the zboiler,asecond meter for the vapor4 going to g the utilizing apparatus, ow`ratio determining means adapted to `be positioned by said meters,

and control means for sai'd regulating means responsive to said flowratio determining means.

10. `In combination, a vapor generating boiler,

the boiler,` regulating. means `for said means, a

- header connected to the boiler, into which thegen'- eratedvapor flows,a vapor utilizinglapparatus t connected to the header for utilizingvaportherel from, a rate of flowl meterior the vaporleavin'g the boiler,- 'aisecond meter for the vapor going to .l

thev utilizing apparatus, flow 'ratio determining means adapted to bepositioned by said meters, l

controlmeans forsaid regulating means responsive to said ratio`determining means, `and vapor pressure responsive means also effectiveupon `said HARVARD H. GORRIE;

r l0 means for supplying elements of combustion to

